Yemen unrest

Smoke rises during clashes between Yemeni security forces and tribesmen loyal to Sheik Sadeq al-Ahmar, the head of the powerful Hashid tribe, in Sanaa, Yemen, on May 31. Heavy fighting resumed May 31 in Yemen's capital between government troops and followers of the country's most powerful tribal leader, ending a brief cease-fire and again raising the prospect that Yemen's political crisis could veer into civil war.